The Islamic State’s (IS) coordinated terror attack staged throughout Paris on the evening of November 13, 2015—Europe’s most deadly urban terror attack in over a decade—signal a simultaneous return to jihadi ideological roots as well as a new era in tactical evolution and strategic ambition.

An American citizen, Ali Muhammad Brown, is accused of executing four men—Leroy Henderson, Dwone Anderson-Young, Ahmed Said, and Brian Tevlin—in a shooting rampage across multiple states, intended as revenge against American policy in the Middle East. In response to investigators' questions, he stated: "All these lives are taken every single day by America, by this government. So a life for a life."